Conventionally, as a thin film solar cell, there has been proposed an integrated thin film solar cell including a transparent conductive film such as ZnO, ITO, or SnCl2 formed on a light-transmitting insulating substrate made of glass or the like, a photoelectric conversion layer formed thereon by successively stacking a p-layer, an i-layer, an n-layer of thin film semiconductor such as amorphous silicon, and stacks of back-surface electrode layers of ZnO/Ag, for example, formed thereon in series, in parallel, or in series and parallel. For example, Patent Document 1 (Japanese Patent Laying-Open No. 2002-314104) proposes that a bus bar coupled to a back-surface electrode layer through a conductive paste is used as an electrode portion for taking out output of a thin film solar cell.    Patent Document 1: Japanese Patent Laying-Open No. 2002-314104